The present disclosure relates to image forming apparatuses.
In some of image forming apparatuses, such as copy machines and multifunction peripherals (MFP), which form images on sheets by electrophotography, a document reading device is disposed in an upper portion of an apparatus body. The document reading device lights a document from the back of a contact glass, to optically read the document by using a CCD (Charge Coupled Device) sensor or the like. To date, the image forming apparatuses including the document reading devices have been known.
In the apparatus body of the image forming apparatus, components such as a drum unit and a toner cartridge are disposed. In the conventional image forming apparatus, the document reading device is provided so as to be openable and closable relative to the apparatus body in order to enable the components to be replaced. When the document reading device is moved upward so as to open, an opening, formed in the apparatus body, which has been closed by the document reading device is opened. Thus, a user is allowed to access the inside of the apparatus body through the opening, thereby enabling the user to, for example, replace a predetermined component.
In the document reading device, a document holder which presses a document against a document placing surface is provided so as to be openable and closable. When a user opens the document reading device, if the document holder is further opened, the document holder may be greatly inclined backward of the apparatus body, and the center of gravity of the entirety of the image forming apparatus may shift and the apparatus body may fall backward. In particular, when the document holder has a document feed device (ADF) mounted therein, the weight of the document holder is increased, so that the apparatus body is more likely to fall backward.
Therefore, the conventional image forming apparatus includes a locking mechanism that locks the document holder so as to prevent the document holder from performing opening and closing operation relative to the document reading device. The locking mechanism includes a document holder locking member disposed in the document holder, and a hook that is pivotably mounted in the document reading device, and is engaged with or disengaged from the document holder locking member. The hook is pivoted in conjunction with the opening and closing of the document reading device, to be engaged with or disengaged from the document holder locking member. Such a locking mechanism allows the document holder to be opened and closed in a state where the document reading device is closed, and locks the document holder so as to prevent the document holder from performing opening and closing operation in a state where the document reading device is opened relative to the apparatus body.